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Subject: Re: [RFC PATCH 3/3 v2] perf: Update perf tool to monitor uncore
 events
From: Lin Ming <ming.m.lin@intel.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>, Ingo Molnar <mingo@elte.hu>,
        Stephane Eranian <eranian@google.com>,
        lkml <linux-kernel@vger.kernel.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Arjan van de Ven <arjan@infradead.org>
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Date: Sun, 21 Nov 2010 22:12:13 +0800
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On Sun, 2010-11-21 at 20:09 +0800, Andi Kleen wrote:
> >
> >              samples  pcnt function               DSO
> >              _______ _____ ______________________
> > ____________________________________
> >
> >                 8.00 18.6% kallsyms_expand_symbol [kernel.kallsyms]
> 
> Reporting a symbol for an uncore event seems highly misleading.
> After all the uncore counter has no idea for which core the event was,
> so there isn't really any instruction pointer to report.
> The event could be event caused by a PCI device or similar.
> 
> For per function monitoring of uncore events one has to use
> OFFCORE_RESPONSE, like I implemented recently.

Let me look at this and then get back to you.

Thanks.

> 
> I would suggest to not report any symbol names for uncore events.
> Doing so just will confuse users.
> 
> In fact I suspect uncore events are only really useful
> with "stat", but not with "top", or if they are used in top
> then the symbol reporting should be disabled.
> 
> -Andi
> 
>